Precedence in the matrix

The defining features of HTTP Switchboard are the precedence/graylisting/inheritance concepts in the matrix.

A "graylisted" matrix cell (pale green or pale red) means the cell inherits its allow or block status from a higher precedence cell in the matrix.

This feature allows the user to whitelist or blacklist a whole group of cells with a single click on a higher precedence cell in the matrix. Here is the tree list of precedence/inheritance in the matrix, from highest to lowest:

• The all cell (top-left corner of the matrix)
  • Types cells (i.e. cookie, css, img, etc.)
    • Specific type and specific domain names (i.e. css/wikipedia.org, img/wired.com, etc.)
      • Specific type and specific subdomain names (i.e. css/en.wikipedia.org, script/www.facebook.com, etc.)
  • Domain name cells (i.e. wikipedia.org, facebook.com, wired.com, etc.)
    • Specific type and specific domain names (i.e. css/wikipedia.org, img/wired.com, etc.)
      • Specific type and specific subdomain names (i.e. css/en.wikipedia.org, script/www.facebook.com, etc.)
    • Subdomain name cells (i.e. en.wikipedia.org, www.facebook.com, video.wired.com, etc.)
      • Specific type and specific subdomain names (i.e. css/en.wikipedia.org, script/www.facebook.com, etc.)

Any explicit whitelist or blacklist status of a cell will cascade down through inheritance to the graylisted cells in the next level. Ultimately, this means that it is possible to control all the cells in the matrix with just the top-left all cell.

Now if you've understood the above tree list, you may have noticed that a single graylisted cell in the middle of the matrix may inherit from two different ancestors: the hostnames (left column) or the type (top row). It is up to the user to choose how this double inheritance works by disabling or enabling "strict blocking (on the Settings page):

• "Strict blocking" disabled: the hostname has precedence over the type, meaning if the hostname is whitelisted, the cell will inherit whitelist status even if the type is blacklisted.
• "Strict blocking" enabled: both the hostname and type have same precedence, meaning both must be whitelisted for the cell to inherit whitelist status.

"Strict blocking" is strongly recommended for security conscious users.

[to do: many animated GIF to illustrate the above]